Cumulative Impacts

Commercial projects are evaluated on an individual basis, without looking at the cumulative impact on intersections, traffic and spillover parking in neighborhoods. Many traffic studies seem to have a finding of “no impact,” yet traffic continues to get worse. What changes in the way we evaluate projects would you favor?

The statement that they don't look at cumulative impacts is misleading – the problem is in how they look at cumulative impacts. Traffic is the best example. The first part of the problem is that there has been a long history of minimizing the size of the problem. For example, the applicant can use a traffic study during an economic downturn as "normal". They can ignore the traffic that will be produced by projects already approved, being built and not yet occupied. They can make unrealistic assumptions about the occupants – for example, the assumption was that the Arbor Real housing project would have very few children (children result in more vehicle trips per household).

The second part of the problem is how you assign responsibility. Consider the situation where anything under 1% increase is regarded as "insignificant". When you look at a major arterial like El Camino, even a major development such as Arbor Real is judged to have insignificant impact. Similarly, the Stanford Industrial Park is not a single property, but a collection of parcels owned by various entities (such as trusts). Consequently, improvements in each rarely have a "significant" impact on Page Mill or the I-280 interchange. The original zoning should have taken into account the carrying capacity of the street, so you might think that if a property gets up-zoning, it should pay for the impacts. But it isn't that simple. A different occupant can generate different levels of traffic and at different times. Consider two properties that replaced their original buildings and stayed within the original zonings: If you charge impact fees based upon the level of congestion when the building was replaced, is that fair to the property owner who waited. And might you not be encouraging the premature replacement of buildings (carbon footprint and waste stream).

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